Aircraft illumination device

ABSTRACT

A system for illuminating parts of an aircraft, such as a helicopter, including three low-intensity position lights (10) mounted on the aircraft, with two of the position lights mounted in a forward location and spaced laterally from the center of the aircraft and a third position light mounted in an aft location centrally positioned on the aircraft. The three position lights provide a triangular light formation that indicates the position of the aircraft during tactical, covert operations. The position lights include a chemiluminescent light source (12) and a housing (22) for carrying the chemiluminescent light source. Each housing is secured to a part of the aircraft by means of a bracket (52) and a pair of band clamps (60). The chemiluminescent light source is visible from within the housing within a limited range of the aircraft. Preferably, the chemiluminescent light source creates an infrared light that is detectable by means of night vision goggles worn by pilots of nearby flying aircraft.

TECHNICAL FIELD

This invention relates to aircraft position lights and, moreparticularly, to low-intensity, anti-collision or collision avoidancelights that are mounted directly to aircraft and/or helicopters forindicating position of the aircraft during tactical, covert,night-flying operations.

BACKGROUND OF THE INVENTION

Tactical, covert, nighttime combat and training flying missions areroutinely conducted by military forces. In these operations, aircraft,particularly helicopters, fly in close formation along the contour ofthe landscape in order to avoid enemy radar, as well as to avoid earlyvisual detection. Such operations are known as "ground-skimming" or"nap-of-the-earth" flights.

It is extremely difficult for pilots to see other aircraft flying information during covert, night-flying missions. Typically, thesemissions are conducted either at night or at dawn or dusk where naturallighting is at a minimum. In addition, since the purpose of suchmissions is to avoid detection, the aircraft fly with their navigationlights turned off. Further, the aircraft are usually painted with highlylight-absorbent paint to make it even more difficult to see the aircraftat night. As a result, the risk of aircraft collisions is greatlyincreased.

To enhance the ability of pilots to see other aircraft in low-levellight conditions, night vision goggles (NVG's), originally used by thearmy and infantry, were developed for military aviation. Generally,these goggles use tiny sensors to amplify electronically ambient lightup to 100,000 times. Green images of night landscapes are displayed ontwo tiny video screens embedded in binocular-like goggles suspended froma pilot's helmet. Sophisticated infrared NVG's can provide images notonly at night, but also in inclement weather.

However, due to the limitations in technology of NVG's, such goggleshave not eliminated the risk of aircraft collisions. For example,military pilots mistakenly attempting to land on other aircraft is acommon type of accident. Many problems associated with NVG's are due tothe single-color lighting, limited field of view, and depth perceptionlimitations of the goggles. Army Times reported in its Mar. 6, 1989issue that between 1978 and 1989, 50 U.S. Army aircraft were involved inaccidents where goggles were worn. These accidents cost the Army morethan $114.6 million in lost aircraft and injuries. To this date,aircraft collisions are a constant concern for the military during suchcovert nighttime operations.

My earlier U.S. Pat. No. 4,916,581 discloses a device for illuminatingthe ends of a helicopter rotor blade by attachment of a chemiluminescentlight stick to the rotor blade's tip. The chemiluminescent lightprovides an indication to the pilot of the helicopter of the position ofthe rotor blade's outer perimeter. However, such a system does notprovide an indication to other pilots of the position and heading of thefuselage of the helicopter. Close formation flying operations requirethat pilots know the position of other aircraft and the direction orheading of the aircraft, which information allows pilots to trackclosely behind other aircraft in formation. With this information,pilots can swiftly and efficiently perform nap-of-the-earth flyingmissions.

Hard-wired, electric non-candescent position light systems are costprohibitive. The installation of such a system would cost many thousanddollars per aircraft. Furthermore, such a system would require constantinspection to ensure its operability, would require regular replacementof defective bulbs or other hardware, and would be subject to unexpectedfailure during use.

The Army has attempted to use a tape-over system for covert, nighttime,training missions. The navigational lights, which are the red, green,and white lights on the aircraft, are taped over with a translucent tapeso that a low-intensity light is given off. While such a system workssatisfactorily in providing a low-intensity light, it is not entirelypractical to use and sometimes is used in contravention of FAAregulations regarding aircraft lighting. When aircraft are required tofly through civilian airspace prior to or during training missions, thetape-over method cannot be used due to the FAA regulations regardingnavigation lights. The aircraft must land when flying into civilian airspace so that the tape can be removed and when flying out of civilianair space into military airspace so that the tape can be added. Thisdelays the training mission and sometimes is not practical for lack of asuitable landing site.

Accordingly, a heretofore unaddressed need exists for a practical andcost-effective, low intensity anti-collision aircraft illuminationsystem for covert night-flying operations.

DISCLOSURE OF THE INVENTION

Briefly described, the present invention comprises a system forilluminating parts of an aircraft wherein the system includes twolow-intensity position lights mounted in a forward location and spacedlaterally from the center of the aircraft and a third low-intensityposition light mounted in an aft location centrally positioned on theaircraft. The three position lights together provide a generallytriangular light formation that indicates to other pilots the positionof the aircraft during tactical, covert, night-flying operations.

Each low-intensity position light includes a chemiluminescent lightsource comprised of a chemiluminescent substance and a translucentcontainer for encapsulating the chemiluminescent substance. A housing isprovided for carrying the chemiluminescent light source. The housingincludes a chamber for receiving the chemiluminescent light source, withthe housing having an opening for inserting and removing thechemiluminescent light source into and from the chamber. The housingalso includes at least one side opening for exposing the translucentcontainer to the exterior of the housing. A bracket is included on thehousing. The bracket is shaped to conform with the aircraft structure towhich the bracket is to be mounted for securing the position light tothe aircraft.

In preferred form, the housing also includes a closure member forclosing off the end opening to the chamber after the chemiluminescentlight source is inserted therein. A lock mechanism may be provided forsecuring the closure member in its closed position with thechemiluminescent light inserted into the housing chamber. Thechemiluminescent light source may be of the type that produces either alow-intensity visible light, an infrared light, or an ultraviolet light.

The position lights are mounted onto the aircraft in a manner so thatthe translucent container of the chemiluminescent light source isexposed rearwardly and to the sides of the aircraft. With two positionlights mounted forward on the aircraft and one position light mountedaft, a triangular light formation is created, which when viewed from thesides or rear, provides pilots of nearby aircraft an indication of theposition of the fuselage of the aircraft. Generally, nearby aircraftflying in formation are located either to the rear or sides of theaircraft.

An infrared chemiluminescent light is picked up easily by night visiongoggles, and low-intensity visible chemiluminescent light can bedetected by pilots not wearing NVG's so long as the respective aircraftare within a limited range. The chemiluminescent light is visuallydetectable only from a distance much less than the audible range of theaircraft. Thus, for example, enemy forces cannot detect thechemiluminescent light and would tend to hear the rhythmic sounds of ahelicopter's rotor blades prior to being able to see thechemiluminescent light.

The chemiluminescent light source is of the type that produces lightwhen two chemical components come into contact with each other. Toactivate the chemiluminescent light, the container is bent until a glassampule containing one of the components within the container breaks,causing the two components to mix. Upon activation, the chemiluminescentlight source typically has a life greater than the fuel capacity of manytypes of aircraft. Thus, the chemiluminescent light source does not needreplacing during flight.

In use, the three chemiluminescent light sources are activated andinserted into the chambers of the housings of the three position lightson an aircraft. During flight, the chemiluminescent light sourcesgenerate a low-intensity light that is easily detected from short rangeby night vision goggles. As stated, the chemiluminescent light sourcesproduce light for at least as long as the flying time of the aircraft.Between flying missions, the translucent containers of thechemiluminescent light sources can be removed with new chemiluminescentlight sources activated and installed in the position light housingsimmediately prior to subsequent missions.

It should be noted that the present invention can be utilized for manytypes of aircraft, although it is primarily directed for helicopter use.In addition, the use of the present invention is not limited to militaryoperations. The chemiluminescent position lights can be used forcivilian aircraft as, for example, in emergency rescue operations.

Other features and advantages of the present invention can be seen andunderstood by examination of the appended drawings, description of thebest mode for carrying out the invention, and the claims, all of whichare incorporated herein by reference as a portion of the disclosure ofthe present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

Like reference numerals are used to indicate like parts throughout thevarious figures of the drawings, wherein:

FIG. 1 is an exploded isometric view of a position light of the presentinvention;

FIG. 2 is a side elevation view of the position light of FIG. 1;

FIG. 3 is an end elevation view of the position light of FIGS. 1 and 2;

FIGS. 4A through 4C are cross-sectional views of the chemiluminescentlight source housings of the position lights of the present invention,with FIG. 4A being taken along the line 4--4 of FIG. 2;

FIG. 5 is a fragmentary side view of the lower portion of a helicopterwith two forwardly-located position lights mounted to the struts of thehelicopter skids;

FIG. 6 is a fragmentary side view of a portion of a helicopter with thetwo forwardly-located position lights mounted on the front tips of thehelicopter skids;

FIG. 7 is a side elevation view of a helicopter with the aft-locatedposition light mounted on the tail skid of the helicopter; and

FIG. 8 is a rear elevation view of a helicopter with a modifiedaft-located position light mounted on the transmission box of the tailrotor.

BEST MODE FOR CARRYING OUT THE INVENTION

Referring now to the drawings, FIGS. 1-3 illustrate a low-intensityposition light 10 that is adapted to be mounted at the front port sideof an aircraft. The other position lights that are mounted at the frontstarboard side and at an aft position on the aircraft are generallysimilar to the position light shown in FIGS. 1-3, with minor variationsthat will be discussed later.

The position light 10 includes a chemiluminescent light source 12 (shownin FIG. 1, but not in FIGS. 2 and 3). The chemiluminescent light source12 may be of the type disclosed in U.S. Pat. Nos. 3,539,794 and3,597,362. By way of example, the chemiluminescent light source 12includes an elongated, tubular, translucent container 14 that has anenlarged headed end 15. An elongated glass ampule 17 is carried withinthe translucent container 14. The glass ampule 17 contains a firstchemical component 18, and the translucent container 14 contains asecond chemical component 20. Such chemiluminescent light sources, whichproduce light when a chemical reaction takes place by two componentscoming into contact with each other, are well known in the art.

The chemiluminescent light source is packaged in a manner that permitsthe chemical components to remain inactive until it is desired to usethe light source and then permits quick and easy activation. When it isdesired to use the device, the translucent container 14 is pressedinwardly or bent at its midsection to cause the inner glass ampule 17 torupture, causing the two components to mix and begin to illuminate or"glow." Hence, the device is simple and easy to operate. These devicesare also available which emit non-candescent light (i.e., light in thenon-visible spectrum), such as infrared or ultraviolet light.

The position light 10 also includes a housing 22 for holding or carryingthe chemiluminescent light source 12. The housing includes an elongatedcylindrical chamber 24 for receiving the translucent container 14. Thecylindrical chamber 24 is closed at its lower end 26 and has an endopening 28 at its upper end. The translucent container 14 is insertibleinto the chamber 24 through the end opening 28.

The chamber 24 includes a set of side openings 28 that extend parallelto one another along a substantial portion of the length of the chamber24. The housing 10 shown in FIGS. 1-3 has three side openings that arearranged in a manner discussed later with reference to FIGS. 4A-4C. Theside openings 28 expose the translucent container 14 to the exterior ofthe housing 22.

The housing 22 includes a closure member 32 that is pivotally secured tothe housing 22 by means of a screw 34. The closure member 32 is movablein the direction of arrow 36 from an open position, as shown in thefigures, to a closed position wherein the end opening 28 of the chamberis closed off. In its closed position, the closure member 32 holds thetranslucent container 14 within the chamber 24.

A rim or flange 38 is provided along a portion of the edge 39 definingthe end opening 28. The flange 38 includes a lip 40 that partiallyoverhangs the edge 39. The closure member 32 includes a projection orflange 44 that is sized to be received beneath the lip 40 in abutmentwith the rim 38. The inner curved edge 45 of the closure member 32 ispartially circular to conform and mate with the lip 40 when the closuremember 32 is closed. A tab 46 is provided for assisting an operator inopening and closing the closure member 32.

A compression spring 48 is provided at the lower end 26 of the chamber24. The compression spring 48 serves the purpose of ejecting thetranslucent container 14 upon opening of the closure member 32 and ofsecurely holding the translucent container 14 within the housing 22against the inner sidewall of the closure member 32 when the closuremember is in its closed position. The force of the translucent container14 against the inner sidewall of the closure member 32 creates africtional engagement between the projection 44 of the closure member 32and the lip 40 of the rim 38. This frictional engagement operates as alocking mechanism and prevents opening of the closure memberinadvertently during flight.

A bracket 52 is mounted at the lower end of the housing 22. The bracket52 and the housing 22 are angularly displaced from one another andreinforced by a gusset 54. The bracket 52 has a concave lower surface56, as best seen in FIG. 3. The concave surface 56 is adapted to conformto a tubular structure to which the bracket is to be mounted on theaircraft. The gusset 54 includes a pair of openings or slots 58, eachfor receiving a band clamp 60. Clamps 60 are well known in the art and,generally, include a band 61 with a series of notches 62 therearound,and an adjustment mechanism 64 for tightening the band. The bracket 52includes a smoothed recess portion 66 at the lateral edge of the bracketadjacent each opening 58. Recesses 66 provide a smooth surface forreceiving the clamps 60.

FIG. 4A is a cross-sectional view of the housing 22 taken along the line4--4 of FIG. 2. FIG. 4A illustrates the angular position of the sideopenings 28 in the housing 22. Two of the openings 28' are equivalent insize and are generally larger than opening 28". The arrangement of theopenings 28 of each housing differentiates the three position lightsfrom each other.

FIG. 4B illustrates a cross-sectional view of the position light mountedat the front starboard side of the aircraft. In the position light shownin FIG. 4B, the two large openings 28' are reversed with respect to thesmaller opening 28" from the openings of the position light shown inFIG. 4A. Thus, with the position light shown in FIG. 4B mounted on thestarboard side of the aircraft and the position light shown in FIG. 4Amounted on the port side of the aircraft, the two smaller openings 28"face generally outwardly of the aircraft. The larger openings 28' faceboth rearwardly of the aircraft and inwardly of the aircraft.

As shown in FIG. 4C, the housing 22 of the position light mounted at anaft location on the aircraft includes three larger openings 28'. Theopenings 28' of the housing 22 of the aft position light are equallyspaced around the periphery of the housing.

The arrangement of the position lights shown in FIGS. 4A-C with respectto each other schematically shows how the position lights would bearranged on the aircraft. So arranged, the side openings of the positionlights would illuminate light generally rearwardly and outwardly to thesides of the aircraft, but not in a forward direction where, forexample, such light may be detected by enemy forces.

FIG. 5 illustrates a typical arrangement for mounting the twoforwardly-mounted position lights. As shown in FIG. 5, the positionlights are mounted to struts 72 between the fuselage 74 of a helicopterand the landing skids 76. In FIG. 5, the front of the helicopter is tothe left of the figure. The side openings 28 of the position lightsgenerally face rearwardly of the helicopter, which, as discussed above,is preferable for avoiding detection by enemy forces. The closuremembers 32 of the housings 22 face rearwardly to some extent so thatairflow past the aircraft will not tend to push open the closuremembers. FIG. 6 illustrates an alternative location for mounting thefront position lights 10. In FIG. 6, the position lights are mounted atthe front tips 80 of the landing skids 76 of a helicopter. Thisarrangement is not preferred to the mounting arrangement shown in FIG.5, but is shown as an alternative method should mounting the positionlights to the struts be impractical. FIGS. 7 and 8 illustratealternative locations for mounting the aft-located position light 10. InFIG. 7, the aft position light is denoted by reference numeral 10' andis mounted on a tail skid 78 that extends rearwardly from the fuselage74 of the helicopter. The position light 10' is mounted to the tail skid78 in a manner so that the side openings 28 of the position light areangled upwardly and face generally rearwardly of the helicopter.

In FIG. 8, the position light 10' is mounted on the transmission box 81of the rear tail rotor 82. In this configuration, the bracket 52 of theposition light is modified to conform to the dimensions of the back sideof the transmission box 81. The bracket 52 is generally triangular inshape, but could be any shape necessary for mounting to the transmissionbox. The housing of the position light remains unchanged and the housingand bracket are still angled with respect to each other. The modifiedbracket is simply mounted onto the transmission box 80 with a set ofbolts.

FIG. 8 also illustrates the triangular configuration of the positionlights. The forwardly-located position lights, referenced as 10", aremounted to the front struts 72 and are spaced laterally from alongitudinal centerline 84 of the aircraft. The aft or rear positionlight is centrally positioned on the longitudinal centerline of theaircraft. The front position lights, together with the rear positionlight 10", form a triangular pattern. The light pattern is used bypilots of nearby aircraft to track the position of the helicopter. Forexample, the two forward position lights 10" indicate to other pilotsthe position of the front of the helicopter, and the rear position light10' indicates the position of the tail assembly of the helicopter, whichinformation provides other pilots the heading of the helicopter. Theposition of the front position lights 10" relative to the horizonindicate the roll of the helicopter, and the position of the frontposition lights relative to the rear position light and the horizonprovides an indication of the pitch of the helicopter. With thisinformation, pilots of other aircraft flying in formation can trackclosely the movement of the other aircraft without straying out offormation and, more importantly, avoiding a collision with otheraircraft. As a result, covert, tactical, night-flying operations can becarried out in a much safer and more efficient manner than theseoperations are currently being conducted.

In operation, a pilot or other maintenance personnel crack thechemiluminescent light sources just prior to taking off. Then, thepilots insert the activated lights into the housings of the positionlights and secure the closure members. These are all the steps necessaryto use the system. During flight, the light source will remainilluminated for several hours, and typically longer than the flying timefor the aircraft. 0f course, a supply of chemiluminescent light sourceswill have to be kept for ready access to replacement light containers.

The housing, bracket, and gusset of the position lights are machinedfrom high-grade aluminum, coated with FAR approved paint, and arevirtually maintenance free. They are simply secured to the aircraft bymeans of clamps or other suitable fasteners. Once secured to theaircraft, inserting and removing the light containers are the onlyrequired steps for use of the system.

It should be noted that the anti-collision position lights of thepresent invention can be used on any aircraft that requires low-levelillumination during low-visibility flying conditions. Thus, it ispossible for the present invention to be used on fixed-wing aircraft aswell as on civilian helicopters.

In addition, the position lights of the present invention eliminate therequirement of landing the aircraft when the tape-over method is used bythe military during training missions. Military aircraft can take offwith the illumination system of the present invention and fly throughcivilian airspace, if necessary, in conformance with FAA regulationswith their navigational lights on. Then, when the aircraft fly intomilitary airspace to begin their training missions, the navigationallights can be turned off and the aircraft are ready to commence trainingflights. No time-consuming additional landings are required.

It is to be understood that many variations in size, shape, andconstruction can be made to the illustrated and above-describedembodiment without departing from the spirit and scope of the presentinvention. Some of the features of the preferred embodiment may beutilized without other features. Therefore, it is to be understood thatthe presently-described and illustrated embodiment is nonlimitive and isfor illustration only. Instead, my patent protection is to be limitedonly by the following claim or claims interpreted according to accepteddoctrines of claim interpretation, including the doctrine of equivalentsand reversal of parts.

What is claimed is:
 1. A system for illuminating parts of an aircraft,comprising:at least three low-intensity position lights mounted on theaircraft, with two of the position lights mounted in a forward locationand spaced laterally from a longitudinal centerline of the aircraft anda third position light mounted in an aft location centrally positionedon the longitudinal centerline of the aircraft, for providing atriangular light formation to indicate the position of the aircraftduring tactical covert operations, each low-intensity position lightincluding:a chemiluminescent light source including a chemiluminescentsubstance and a translucent container for encapsulating thechemiluminescent substance, a housing for holding the chemiluminescentlight source, the housing including a chamber for receiving thechemiluminescent light source, an opening for inserting and removing thechemiluminescent light source into and from the chamber, and at leastone side opening for exposing the translucent container to the exteriorof the housing, and a bracket portion for securing the housing to theaircraft.
 2. The system of claim 1, wherein the housing includes aclosure member for closing off the opening of the chamber upon insertionof the chemiluminescent light source into the chamber, and a lockmechanism for securing the closure member in its closed position.
 3. Thesystem of claim 1, wherein the chemiluminescent substance produces aninfrared light.
 4. The system of claim 1, wherein the chemiluminescentsubstance produces an ultraviolet light.
 5. The system of claim 1,wherein the bracket and the chamber are angled with respect to eachother in order to expose the side opening of the housing to the rear ofthe aircraft upon mounting the bracket to a horizontal surface of theaircraft.
 6. The system of claim 1, wherein the side opening of thehousing includes a portion exposing the translucent container to theport side of the aircraft, a portion exposing the translucent containerto the starboard side of the aircraft, and a portion exposing thetranslucent container to the rear of the aircraft.
 7. The system ofclaim 1, wherein the bracket includes a slot for receiving a clamp tosecure the position light to the aircraft.
 8. The system of claim 1,wherein the chamber of each housing includes a compression springopposite the end opening of the housing.
 9. The system of claim 1,wherein the aircraft on which the position lights are mounted is ahelicopter.
 10. The system of claim 9, wherein the two position lightsmounted in a forward location are mounted on the struts supporting thefuselage skids of the helicopter and the position light mounted in anaft location is mounted on the tail assembly of the helicopter.
 11. Thesystem of claim 10, wherein the bracket of each low-intensity light isconcave to conform to a tubular structure on the helicopter.
 12. Thesystem of claim 1, wherein the bracket portion is shaped to conform withthe aircraft structure to which the position light is to be mounted.